The longest continuously running line of Patek Philippe watches, the perpetual calendar chronograph with moonphases is a cornerstone of the company’s production, with all its representatives being extremely collectible and some of them considered the ultimate tier of Patek Philippe production.

Most collectors can easily describe the general aesthetics of the line: three counters at 3, 6 and 9 o’clock, moonphases at 6, two windows at 12, and a round case - traits which are shared among all the five references which encompass the series: 1518, 2499, 3970, 5970 and 5270.

And yet, the aforementioned reasoning is if not wrong at the very least incomplete: it fails to take into account present reference 5020, the sixth representative of the line and the one and only NOT sporting a round case, but rather a cushion one. A most unusual design choice, it is reminiscent of the 1920s production of the firm and was not very well received at the time, resulting in the most scarce output among the four modern references (3970, 5970, 5270 and indeed 5020): about 750 examples were made in all metals from 1994 to 2002, with pink gold specimens being only circa 150. The Breguet numerals amplify the vintage charm of the piece, while the case architecture grants it remarkable wrist presence and renders it surprisingly in tune with today’s taste.

While it arguably is one of the most collectible Patek Philippe references in virtue of its looks, inherent scarcity and design uniqueness, its rarity implies that it is a model very seldom seen on the market, and thus the collectors community is still relatively little aware of its importance (and sometimes its existence), making it at the moment one of the most attractive propositions for the foresighted collector of rare and important timepieces.